This invention is the field of polyamide compositions; more particularly, the invention relates to a polyamide composition for use in rotational molding and a method for the rotational molding of the composition.
Rotational molding, also known as rotomolding, is used in the manufacture of hollow objects from thermoplastics. In the basic process of rotational molding, solid or liquid polymers are placed in a mold. The mold is first heated and then cooled while being rotated about two perpendicular axes simultaneously. Many polymers can be used in the rotational molding process. Popular polymers for this use are polyolefins such as polyethylene. It is also known to use polycarbonates, crosslinkable polyethylene, nylon, and other materials. In selecting the rotational molding grade formulation, care must be taken to assure that there will not be thermal degradation during the heating cycle. A general discussion on rotational molding is given in MODERN PLASTICS ENCYCLOPEDIA 1979-1980, Volume 56, No. 10A, beginning at Page 381.
It is known to use small amounts of conducting fillers in rotationally molded articles. U.S. Pat. No. 3,733,385 discloses that 0.1 to 2% by weight of a conducting filler can be used to make rotationally molded articles.
U.S. Pat. No. 4,042,559 discloses an abrasive resistant coated abrasive pipe lining sheet.